Laryngoscopes are medical devices which are employed to introduce endotracheal tubes into patient's airways, for example, when a patient is being anaesthetised. Laryngoscopes comprise insertion sections, which are the part of a laryngoscope which extends towards and into a patient's oral cavity during intubation. Insertion sections may be removably attachable to a laryngoscope body, integral parts of laryngoscopes or themselves function as laryngoscopes. As well as an insertion section, laryngoscopes typically comprises a handle which is usually elongate and which may be arranged at an angle to the proximal end of the insertion section or generally parallel to the proximal end of the insertion section, or at any angle therebetween. Laryngoscopes further include a source of light and a number of known devices, referred to as video laryngoscopes, include imaging devices, for example integral video cameras or fibre-optic bundles for attachment to external video cameras, to enable a user to view the distal tip of an endotracheal tube as it is being introduced into a patient's larynx.
Traditional laryngoscope insertion sections, such as insertion sections known in the art as Miller, Macintosh or Wisconsin blades, function to lift a patient's tissue adjacent the epiglottis to enable a tube to be inserted into a patient's larynx and to enable the patient's larynx to be viewed during intubation. However, they do not guide tubes as such.
A number of designs are known which do include a tube guide. For example, WO 04/073510 (Gandarias) discloses a laryngoscope having a lateral tube guide extending along the majority of the length of the insertion section. A tube guide enables an endotracheal tube to be detachably retained by the insertion section while it is introduced into a patient's larynx. In principal, the provision of a tube guide may facilitate intubation by introducing the endotracheal tube into the oral cavity at the same time as the insertion section and by directing a tube towards the larynx. However, tube guides increase the overall bulk of insertion sections and it is desirable to provide a tube guide which adds as little bulk as possible to the insertion section.
Endotracheal tubes come in a wide range of external diameters, for use with patients of different dimensions. Laryngoscope insertion sections with tube guides are typically only suitable for intubating using endotracheal tubes having a relatively narrow range of external diameters. Thus, insertion sections must typically be provided with tube guides in a range of sizes. Not only does this increase manufacturing costs and require users to stock several types of insertion section, there is a risk that the wrong sized insertion section might be selected during intubation, or that a user may not have the correct size of insertion section for use with an endotracheal tube having a particular external dimension appropriate to the patients who is to be intubated.
In order to enable an insertion section to be used with insertion sections of a wide range of external diameters, a tube guide may be provided which is of fixed relatively broad cross-section, such as to be able to retain endotracheal tubes of up to a predetermined maximum external diameter. However, any such tube guide is unlikely to adequately guide tubes having a relatively small external diameter.
Furthermore, any such tube guide will be bulkier than is necessary when retaining and guiding endotracheal tubes of relatively small external diameter.
Accordingly, the invention aims to provide a laryngoscope insertion section with a tube guide which reliably guides endotracheal tubes of a relatively wide range of external diameters. Some embodiments of the invention aim to provide a laryngoscope insertion section which is usable to reliably guide endotracheal tubes of a wide range of external diameters without being excessively bulky when guiding endotracheal tubes with external diameters at the lower end of an operating range of endotracheal tube size.